1. Technical Field
This invention relates generally to methods of forming tubular members, and more particularly to methods of rolling and welding tubular members.
2. Related Art
It is well known to form metal tubular members from flat sheet material by rolling a fixed length of the sheet material into a tubular form and then welding abutting ends of the rolled sheet to one another to formed a length-wise extending welded seam. However, in forming rolled tubular members, challenges remain in being able to form the tubular member having tightly controlled inner or outer diameter tolerances. Further, challenges remain in being able to form the tubular member having a purely cylindrical shape. Typically, a flat surface is formed immediately adjacent the welded seam, resulting from a small segment of the flat sheet material not being curled. Further yet, challenges remain in forming tightly controlled diameter tolerances due to inherent variation in the actual sheet material thickness due to thickness tolerances of the sheet material. Accordingly, the inner and/or outer diameter of formed with one sheet material thickness is generally different from the inner and/or outer diameter of another sheet material thickness. When these tolerances are critical to the performance of the tubular member and components associate therewith, the useful life of the tubular member and/or components can be reduced.
A method of forming a tubular member from a generally flat piece of metal sheet material in accordance with invention overcomes the challenges discussed above, as well as others, which will be readily apparent to those possessing ordinary skill in the art of forming tubular members from metal sheet material.